[Bug tree-optimization/115143] [11/12/13/14/15 Regression] tree check: expected class 'type', have 'exceptional' (error_mark) in useless_type_conversion_p, at gimple-expr.cc:85

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115143

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
here is the simplified gimple testcase so it does not depend on optimizations
before hand:
```
unsigned __GIMPLE (ssa,startwith("phiopt"))
foo (unsigned a, unsigned b)
{
  unsigned j;
  unsigned _23;
  unsigned _12;

  __BB(2):
  if (a_6(D) != 0u)
    goto __BB3;
  else
    goto __BB4;

  __BB(3):
  j_10 = __PHI (__BB2: b_11(D));
  _23 = __MIN (a_6(D), j_10);
  goto __BB4;

  __BB(4):
  _12 = __PHI (__BB3: _23, __BB2: 0u);
  return _12;

}
```


Here is one which failed since GCC 10 (when __MIN support was added for gimple
FE):
```
signed __GIMPLE (ssa,startwith("phiopt"))
foo (signed a, unsigned b)
{
  signed j;
  signed _23;
  signed _12;

  __BB(2):
  if (a_6(D) > 0)
    goto __BB3;
  else
    goto __BB4;

  __BB(3):
  j_10 = __PHI (__BB2: b_11(D));
  _23 = __MIN (a_6(D), j_10);
  goto __BB4;

  __BB(4):
  _12 = __PHI (__BB3: _23, __BB2: 0);
  return _12;

}
```